Details

Autor(en) / Beteiligte

• Wang, Hong-Gang
• Zhang, Jian-Han
• Lin, Ming-Shui
• Wang, Tian-Yu
• Zhang, Zhi-Jian
• Yan, Shufeng
• Ying, Shao-Ming

Titel

Flux synthesis, crystal structure, and characterization of a gamma-vanadate selenite polymorph

Ist Teil von

• Journal of solid state chemistry, 2022-04, Vol.308, p.122928, Article 122928

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• Our exploration in vanadate selenites by using boric acid flux method has successfully lead into a new phase, namely, γ-V2Se2O9. Single crystal X-ray diffraction indicates its a new structure which crystallizes in monoclinic space group P21/c with a lattice parameter of a ​= ​7.4857 (12) Å, b ​= ​7.4388 (8) Å, c ​= ​13.042 (2) Å, β ​= ​106.619 (9)°. Its crystal structure features novel 2D electroneutral [V2Se2O9] layers composed of 1D [V2SeO9]4- chains that are further bridged by Se (1)O3 triangular pyramids. [V2SeO9]4- chain consist corner-sharing of VO6 and tridentate Se (2)O3. Unlike previously reported α- and β-V2Se2O9 with isolated [V4O18]16− tetramers, corner-sharing of VO6 octahedra lead into a 1D [V2O9]8- chain in γ-V2Se2O9. X-ray powder diffraction and thermal behavior analysis were performed to study its phase purity and thermal stability. Optical diffuse reflectance spectra associated with Tauc's fitting indicates a direct bandgap semiconductor with an energy value of 2.34 ​eV, which consistent with the theoretical prediction. As a compare, the electronic bandgaps of three polymorphs were studied and shows a sequence of α-V2Se2O9<β-V2Se2O9<γ-V2Se2O9. Density of states were also calculated to reveal the origin of the bandgaps and bond interactions. [Display omitted] γ-V2Se2O9 was obtained by boric acid flux method in vanadate selenite system. Its crystal structure features novel 2D electroneutral [V2Se2O9] layers composed of 1D [V2SeO9]4- chains that are further bridged by Se (1)O3 triangular pyramids. [V2SeO9]4- chain consist corner-sharing of VO6 and tridentate Se (2)O3. UV–Vis diffuse reflectance spectroscopy coupled with Tauc's analysis indicates a direct semiconductor with a bandgap value of 2.34 ​eV, and its energy transition type was further supported by first-principles electronic structure calculation. •γ-V2Se2O9 was obtained by boric acid flux method for the first time.•Unlike α- and β-V2Se2O9 with isolated [V4O18]16− tetramers, corner-sharing of VO6 forms 1D [V2O9]8- chains in γ-V2Se2O9.•UV–Vis diffuse reflectance spectroscopy coupled with Tauc's fitting indicates γ-V2Se2O9 as a direct bandgap of 2.34 ​eV.